1. Field of the Invention
The present invention relates to an interdigitated microelectrode biosensor, and more specifically to a hydrogel-based interdigitated microelectrode biosensor in which a hydrogel is provided between interdigitated microelectrodes such that the presence and concentration of a biological substance, particularly a protein, are detected by measuring the impedance between the interdigitated microelectrodes, achieving increased impedance detection width and limit by tens to hundreds of times and improved impedance detection accuracy compared to conventional interdigitated microelectrode sensors.
2. Description of the Related Art
In recent years, many biosensors have been developed for detecting the presence and concentration of a variety of biological substances, such as genes and proteins, by electrical methods. One example is to use interdigitated microelectrodes. Since biosensors using interdigitated microelectrodes have a very substantially broad region in a zigzag configuration where receptors capable of specific binding to a biological substance are immobilized, they are praised for their ability to measure even a low concentration of the biological substance.
Such a biosensor using interdigitated microelectrodes is disclosed in Korean Patent No. 777973 (published on Nov. 29, 2007). According to this patent, since the concentration of a biological substance is measured based on an electric current flowing between the electrodes, it is necessary to use conductive particles for the flow of electric current between the electrodes. However, the use of the conductive particles is troublesome.
The biosensor has the problem that a larger amount of an electric field having an influence on the impedance between the electrodes escapes upward from the electrodes than the amount generated between the electrodes. That is to say, the impedance variation is more affected by changes generated above the electrodes than by reactions generated between the electrodes. As a result, a narrow width and a low limit of impedance detection as well as a low accuracy of impedance detection are obtained, implying poor reliability and availability of the sensor.